1972 Johnson 2HP Outboard Motor Service Manual, Page 13Get this manual
TUNE-UP PROCEDURE
When owner brings motor to for tune-up, for some minor operating malfunction, the following procedure should used as guide to determine the cause of the ma1functionWrite down the owner' commentsan accurate card file service shop operationEach service operation should record as to the: OWNER'S NAME DATE MODEL NOSERIAL NONATURE OF COMPLAINT NATURE OF WORK PERFORMED COST OWNER WAS WORK PERFOMED UNDER WARRANTY? After writing down the owner's comments, check the motor visually and begin systematic tune-up procedureConsult the Check Chart to find the causes of ma1function which discovered when tuning the motor1Remove exhaust cover and cylinder headSlowly rotate flywheel and visually inspect piston, rings, and cylinder for wear, freeness, and carbon deposits
Piston ring condition should determined before continuing tune-upGum and varnish deposits rings piston removed with an application of Accessory Engine CleanerIf piston, cylinder, and rings
considered to in satisfactory condition for continued service, clean reinstall cover, using new gasketClean from cylinder head and top of pistonDo not alter piston deflectorSurface and reinstaH cylinder head, using new gasket